Research Review by Dr. Shawn Thistle©

Date:

June 2008

Study Title:

The disabled throwing shoulder: Spectrum of pathology Part III: The SICK Scapula, Scapular Dyskinesis, the kinetic chain, and rehabilitation

Authors:

Burkhart SS, Morgan CD, Kibler B

Authors’ Affiliations: Not listed (all authors are American orthopedic surgeons)

Publication Information:

Arthroscopy: The Journal of Arthroscopic and Related Surgery 2003; 19(6): 641-661.

Summary:

Overhead sports participation is very common, as are associated shoulder injuries. This important paper (Part 3 of a 3 part series) was published to put years of clinical and surgical observation by three of the leading shoulder experts in the United States into usable clinical concepts that can be applied in practice. Although published a few years ago (2003), it still represents the most comprehensive explanation of these concepts that will change the way you view and assess shoulder mechanics, pathology, and injuries in throwing or overhead athletes (and I would argue the general population as well). An executive summary of this paper follows. Please be sure to review Part 1 of this series to re-familiarize yourself with the basic concepts behind this work.

The “Dead Arm” syndrome described in the first part of this review series can have numerous causes, as can shoulder pain in general. One of these is a muscular fatigue syndrome with the hallmark feature of asymmetric scapular malposition in the dominant throwing shoulder. These authors have coined the term SICK Scapula to describe this phenomenon, which can present clinically with three recognizable patterns of altered kinematics, or Scapular Dyskinesis, which will be described below. The authors describe a concept of “the shoulder at risk” – one that is potentially asymptomatic, but exhibits GIRD (see Part 1 of this series) and a malpositioned SICK scapula (see below) – keep this in mind as you continue to read this review.

S.I.C.K. SCAPULA SYNDROME

SICK is an acronym used to describe this condition – which stands for: Scapular malposition, Inferior medial scapular border prominence, Coracoid pain and malposition, and dysKinesis of scapular movement. Patients with SICK scapula syndrome typically present with:
  • anterior shoulder pain, particularly in the coracoid region*
  • posterior-superior scapular pain
  • proximal lateral arm pain
  • pain radiating to the ipsilateral cervical region
  • arm pain similar to thoracic outlet syndrome (rare)
  • any combination of the above
The authors note that by far, *the most common presenting complaint is anterior shoulder pain in the region of the coracoid, particularly the medial aspect at the attachment of the pectoralis minor tendon. This can easily be confused with pain from anterior instability. This may be associated with lack of full forward flexion, with further pain exacerbation with passive forward flexion by the examiner. The clinician should be able to observe a static asymmetry between the shoulder blades (normally, the dominant side is lower). The static position can be suggestive of specific underlying muscle activation alterations, which manifest in certain patterns during motion. Clinicians should observe and evaluate the involved scapula for inferior migration, lateral displacement, and abduction (Note: the authors admit that clinical measurement of these malpositions is open to inter-rater inconsistencies).

Evaluating these three aspects of scapular position will provide (at minimum) a qualitative sense of the severity of dyskinesis. These altered static positions fall into three clinically recognizable patterns, each described below (please be aware that combinations are possible).

Type 1: Inferior Medial Scapular Border Prominence
  • commonly associated with labral injuries/lesions
  • exhibits lack of acromial elevation
  • exhibits lack of full retraction and cocking
  • associated with tightness/inflexibility of the pec minor/major and inhibition/weakness of the lower trapezius and serratus anterior
Type 2: Medial Scapular Border Prominence (more evident with cocking)
  • commonly associated with labral injuries/lesions
  • little or no anterior inflexibility
  • associated with weakness of upper/lower trapezius and rhomboids
Type 3: Superior Medial Scapular Border Prominence
  • commonly associated with rotator cuff pathology such as impingement syndromes, rather than labral lesions
  • associated with positive impingement tests and findings
The Rotational Unity Rule:
  • If GIRD (glenohumeral internal rotation deficit) exceeds the external rotation gain (ERG) in a throwing shoulder with a GIRD:ERG ratio > 1, the shoulder is “headed for trouble” due to the posterior superior shift of the glenohumeral rotation point in the cocking phase, placing the labrum at risk of injury.
Kinetic Chain Considerations in SICK Scapula:
  • Legs and Trunk: provide a stable base for arm motion, contributing up to 55% of force to a tennis serve. Inflexibility of the non-dominant hip or trunk rotation, weakness of the hip abductors or trunk flexors can disturb the force transmission pattern.
General Treatment Approach and Prognosis:
The primary focus of treatment for SICK scapula is non-operative musccular rehabilitation. Initially, the thrower is restricted from all throwing and placed on a regimented rehabilitation program. The authors report that patients who commit to performing the rehabilitation exercises 3x/day can achieve a 50% repositioning effect on the involved scapula within 2-3 weeks.

Once this 50% improvement has been achieved, the athlete can be placed on an interval throwing program (3-4 weeks). Once return to sport is achieved, it is recommended that rehabilitation and strengthening exercises are performed every other day to prevent recurrence.

Rehabilitation of the Overhead Athlete with SICK Scapula:
  • should include the kinetic chain from the outset, using combinations of movements that include trunk extension and scapular retraction, trunk rotation and scapular retraction, and 1-legged stance and diagonal trunk rotation with scapular retraction (all of these share a common goal of lower trapezius activation)
  • initial scapular exercises (Note: these exercises are best seen/learned in a hands-on environment. RRS recommends taking a seminar/course on this topic to appropriately master these and other exercises): scapular punches, “low row”, isometric retractions, scapular clock, wall washes
  • scapular stability training as above should be performed prior to higher level rotator cuff strengthening
  • stretching should be directed at the pectoralis muscles (foam roller, door stretch), and the posterior GH capsule using the sleeper stretch or cross-arm stretch
  • further exercises can include: open chain forward and lateral lunges and diagonal pulls, Blackburn retraction exercises (and although not mentioned in this paper, the Buchberger 12 routine would be appropriate as well), push-ups (seated and conventional), rowing exercises, and so on

Conclusions & Practical Application:

This paper outlined the concept of the SICK scapula, and provided suggestions for clinical observation and rehabilitation of this condition. The reader should remember the basic concepts from the first paper, including a unifying theory of pathology in elite throwing shoulders, which can be summarized by identifying the following “Culprits”:
  • tight posterior capsule (that is often clinically silent)
  • GIRD: glenohumeral internal rotation deficit
  • excessive peel-back forces leading to a SLAP lesion
  • hyperexternal rotation causing a shift in the pivot point and a reduction in the cam effect on the anterior capsule (which may be mistaken for anterior instability)
  • scapular protraction, and poor scapular stability

Additional Resources:

  • Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: Spectrum of pathology Part I: Pathoanatomy and biomechanics. Arthroscopy: The Journal of Arthroscopic and Related Surgery 2003; 19(4): 404-420.
  • Kibler WB. The role of the scapula in athletic shoulder function. American Journal of Sports Medicine 1998; 26(2): 325-337.